Abstract
The objective of this research is to study the attack angle effect of elongated orifice with aspect ratio of AR = 8 on the flow and heat transfer characteristics of jet impingement array. Both the inline and staggered arrangements, having arrays of 6×4 nozzles and attack angles at θ = 0°, 15°, 30° and 45°, were examined. The jet-to-plate distance (H) and the jet-to-jet distance (S) were fixed at H = 2D_E and S = 3D_E, respectively (where D_E is the equivalent diameter). The experiments were carried out under jet Reynolds number at Re = 13,400. Temperature distributions on the impingement surface were measured using Thermochromic Liquid Crystal sheet (TLCs). Flow characteristics on the impingement surface were visualized using the oil film technique. Numerical simulation was employed to gain insight into the fluid flow via Computational Fluid Dynamics (CFD). The results indicate that the average heat transfer on the impingement surface tends to decrease when the attack angle becomes larger. However, local heat transfers at impingement regions in the upstream channel with attack angles of θ = 30° and 45° are higher than those at θ = 0° and 15°, especially in the case of staggered arrangement.
